Area Forecast Discussion
Issued by NWS Riverton, WY

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FXUS65 KRIW 240550
AFDRIW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
1150 PM MDT THU OCT 23 2014

.SHORT TERM...TONIGHT AND FRIDAY

THE RIGHT FRONT QUAD OF A STRONG 160KT UPPER JET WILL CONTINUE TO
IMPACT THE FORECAST AREA INTO FRIDAY MORNING KEEPING VERY STRONG
WESTERLY WINDS ON THE LEE SIDE OF MOUNTAIN RANGES. CHIEF JOSEPH
MEASURED A 71 MPH AT 9 PM THIS EVENING. THE STRONGEST WINDS ARE
EXPECTED TO OCCUR THROUGH 12Z OVER THE ABSAROKA MTS...WITH THE
BULK OF THE STRONGEST WINDS REMAINING ABOVE THE CODY FOOTHILLS.
SPS STILL LOOKS GOOD IN THOSE AREAS. THERE REMAINS A SLIGHT CHANCE
OF A FEW SHOWERS OVER NORTHWEST WYOMING...MAINLY YELLOWSTONE
THROUGH FRIDAY MORNING. UPPER RIDGE BEGINS TO BUILD INTO THE AREA
FRIDAY...WITH DECREASING CLOUDINESS IN THE AFTERNOON...AND WINDS
NOT BEING AS STRONG IN MANY AREAS...ESPECIALLY IN THE MOUNTAINS.

.LONG TERM...FRIDAY NIGHT THROUGH THURSDAY

WARM RIDGE BUILDS OVER THE SRN ROCKIES AND HIGH PLAINS LEADING TO A
VERY MILD SATURDAY WITH H7 TEMPERATURES BETWEEN +6C AND +9C. A FEW
TEMPERATURES RECORDS ARE STILL POSSIBLE...ESPECIALLY IN CENTRAL WYO
WHERE READINGS WILL BE IN THE 70S FOR MOST AREAS. THEN WE START A
SIGNIFICANT CHANGE AS THE ERN PACIFIC UPPER LOW MOVES IN. THE SRN
PART OF THIS TROUGH MOVES IN FIRST ON SUNDAY INTO SUNDAY NIGHT WITH
THE NRN PIECE FOLLOWING QUICKLY BEHIND SUNDAY NIGHT AND MONDAY.
STILL A LOT OF DIFFERENCES IN THE DETAILS BUT ENOUGH COLD AIR WITH
THIS SYSTEM FOR SNOW OUT WEST SUNDAY WITH POTENTIAL FOR SNOW LINE
LOWERING TO THE VALLEY FLOOR. EAST OF THE DIVIDE...THE COLD AIR
FILTERS IN SUNDAY NIGHT WITH POTENTIAL FOR RAIN CHANGING TO SNOW
ACROSS THE NORTH AND THEN SPREADING INTO PARTS OF CENTRAL WYO LATER
SUNDAY NIGHT OR MONDAY MORNING. NOT A REAL ORGANIZED OR CLOSED OFF
SYSTEM BUT ENOUGH FORCING...OROGRAPHICS OUT WEST AND SOME
FORCING...UPSLOPE EAST TO GENERATE SOME LIGHT TO MODERATE SNOWFALL IN
THE MOUNTAINS AND POTENTIAL FOR SOME ACCUMULATION IN THE LOWER
ELEVATIONS EAST OF THE DIVIDE ALSO. WILL CONTINUE TREND OF
INCREASING POPS IN THE WEST SUNDAY AND THEN KEEP HIGH POPS IN THE
WEST INTO SUNDAY NIGHT WHILE INCREASING THEM IN THE NORTH AND THEN
WORKING SOUTH INTO MONDAY BEFORE THE SYSTEM MOVES OFF TO THE EAST
AND SOUTH. BRIEF RIDGING TUESDAY BEFORE THE NEXT SHORTWAVE IN THE NW
FLOW MOVES IN TUESDAY NIGHT AND WEDNESDAY. GFS HAS ANOTHER SYSTEM
MOVING INTO THE NRN PLAINS THURSDAY WITH A FRONT DROPPING SOUTH
ACROSS OUR NRN AND ERN ZONES. THE ECMWF HAS A RIDGE AHEAD OF A
POTENTIAL SYSTEM BEYOND THE MEDIUM RANGE. STILL A LOT OF AT THE END
OF THE PERIOD AS TO THE EVOLUTION/MOVEMENT OF OUR SYSTEMS OVER
SIBERIA AND MOVING EWD. OP ECMWF AND GFS SHOW MORE SPLITTING WITH
THIS SYSTEM AND THUS MUCH MORE ENERGY/UPPER LOW FORMING OVER THE ERN
PACIFIC LATE NEXT WEEK. THE GFS HAS A LITTLE MORE ENERGY RIDING OVER
THE AK RIDGE EARLY NEXT WEEK AND THUS A STRONGER SYSTEM DIVING INTO
THE NRN HIGH PLAINS ON THURSDAY WITH MAINLY DRY FRONTAL SYSTEM
IMPACTING OUR AREAS EAST OF THE DIVIDE. CONFIDENCE STILL LOW ON THE
LAST COUPLE DAYS OF THIS PERIOD AND BEYOND WITH MORE ACTIVE
HEMISPHERIC 5 WAVE DEVELOPING.

&&

.AVIATION.../06Z ISSUANCE/

CONCERN FOR THE REST OF TONIGHT AND FRIDAY WILL BE CONSIDERABLE
MOUNTAIN TURBULENCE WITH STRONG MOUNTAIN TOP WINDS...ESPECIALLY
THROUGH FRIDAY MORNING. LLWS ON THE LEE SIDE OF MOUNTAIN RANGES IS
EXPECTED FRIDAY MORNING AT COD AND LND...BUT IT IS EXPECTED TO
IMPROVE THROUGH THE MORNING HOURS. CONSIDERABLE HIGH AND MID LEVEL
CLOUDINESS THIS MORNING ARE EXPECTED TO WILL BECOME MAINLY SKC
BETWEEN 20Z AND 00Z. THERE COULD BE ISOLATED SHOWER ACTIVITY OVER
EXTREME NW WYOMING THIS MORNING...BUT SHOULD NOT IMPACT COD OR
JAC. THUS VFR AND DRY CONDITIONS WILL OCCUR AT AREA TERMINALS
THROUGH TAF VALID PERIOD...WITH BREEZY TO WINDY CONDITIONS BEING
THE MAIN CONCERN TODAY.

PLEASE SEE THE AVIATION WEATHER CENTER FOR THE LATEST INFORMATION ON
TURBULENCE FORECASTS.

&&

.FIRE WEATHER...

THE MAIN CONCERN FOR THE REMAINDER OF TONIGHT INTO FRIDAY WILL BE
THE STRONG WINDS OCCURRING THE MOUNTAINS AND IN THE TYPICAL WIND
CORRIDORS. OVER THE LOWER ELEVATIONS OF NATRONA COUNTY /FIRE
WEATHER ZONE 280/ THERE BE A COMBINATION OF LOW RH BETWEEN 15 AND
20 PERCENT AND BREEZY WINDS TO CREATE ELEVATED FIRE BEHAVIOR.
THERE COULD BE ISOLATED SHOWERS OVER EXTREME NORTHWEST WYOMING
THROUGH FRIDAY MORNING...BUT THEY WILL BE VERY LIGHT AND NO
WETTING RAIN WILL OCCUR.

&&

.RIW WATCHES/WARNINGS/ADVISORIES...NONE.

&&

$$

SHORT TERM...TEAM RIVERTON
LONG TERM...SKRBAC
AVIATION...WM
FIRE WEATHER...TEAM RIVERTON





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